等差數(shù)列{

}的前n項和為

,則常數(shù)

= ( )
試題分析:因為

為等差數(shù)列的前n項和,所以

。
點評:熟記等差數(shù)列前n 項和的性質(zhì):等差數(shù)列前n項和的形式一定為

的形式,一定要注意不含常數(shù)項。這條性質(zhì)在選擇題和填空題中可以直接應(yīng)用。
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科目:高中數(shù)學(xué)
來源:不詳
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(本小題滿分12分)a
2,a
5是方程x
2-12x+27=0的兩根,數(shù)列{

}是公差為正數(shù)的等差數(shù)列,數(shù)列{

}的前n項和為

,且

=1-

(1)求數(shù)列{

},{

}的通項公式;
(2)記

=


,求數(shù)列{

}的前n項和Sn.
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當(dāng)

為正整數(shù)時,定義函數(shù)

表示

的最大奇因數(shù).如
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,

,….記

.則
.(用

來表示)
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
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共線;
②命題:“

”的否定是“

”;
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
在(0,1)沒有零點,則k的取值范圍是

④

是定義在R上的奇函數(shù),

的解集為(

2,2)
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
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
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,若

,則

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
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,且

,(
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=1,2,3…)
(1)求數(shù)列

的通項公式;
(2)記

,求

.
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來源:不詳
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(本小題滿分13分)設(shè)數(shù)列

的前

項和為

,且

;數(shù)列

為等差數(shù)列,且

。

求證:數(shù)列

是等比數(shù)列,并求

通項公式;

若

,

為數(shù)列

的前

項和,求

。
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科目:高中數(shù)學(xué)
來源:不詳
題型:解答題
(本小題滿分13分)設(shè)數(shù)列

的前

項和為

.已知

,

,

.
(1)寫出

的值,并求數(shù)列

的通項公式;
(2)記

為數(shù)列

的前

項和,求

;
(3)若數(shù)列

滿足

,

,求數(shù)列

的通項公式.
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科目:高中數(shù)學(xué)
來源:不詳
題型:單選題
已知等差數(shù)列

的前項和為

,若

三點共線,

為坐標(biāo)原點,且

(直線

不過點

),則

等于 ( )
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